Walk power mower with height of cut adjustment system having spring arm with replaceable locking pin

ABSTRACT

A walk power mower has a mower deck that encloses a pair of rotary cutting blades with the grass clippings from the blades being discharged through a rearwardly extending grass discharge tunnel in a rear bagging mode of operation. The mower deck has ground engaging wheels that are vertically moved up or down to adjust the height of cut. The height of cut adjustment system comprises at least one spring arm having a locking pin or tab that cooperates with one of a plurality of notches, detents or openings on the mower deck to select a desired height of cut. A threaded fastener releasably attaches the locking pin or tab to the spring arm to be able to replace the locking pin or tab without replacing the entire spring arm.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 13/312,433 filedDec. 6, 2011.

TECHNICAL FIELD

This invention relates to mowers and, more particularly, to walk powermowers which are operated by a user who walks on the ground behind themower when operating the mower.

BACKGROUND OF THE INVENTION

Walk power mowers are well known for cutting grass. Such mowers arecharacterized by a relatively small mower deck, typically one thatprovides a 21″ cutting width, which is supported by four wheels at thecorners of the deck for rolling over the ground. The underside of thedeck typically includes a substantially circular cutting chamber. Thecutting chamber houses a single rotary cutting blade that rotates abouta substantially vertical axis in a substantially horizontal cuttingplane. A small internal combustion engine or electric motor is laterallycentered on top of the mower deck. The shaft of the engine or motorextends down through the top wall of the mower deck into the cuttingchamber to be attached to the cutting blade.

Many mowers of this type have a rear bagging mode in which the grassclippings are thrown into and collected within a bag that is releasablyfastened to the rear of the mower deck. In such mowers, the cuttingchamber has a rearwardly extending discharge tunnel that progressivelyincreases in height as it extends rearwardly to accommodate the grassclippings. The tunnel ends in a rearwardly facing grass dischargeopening that is mated to the open mouth of the bag. Desirably, thetunnel and the bag are positioned so that they do not extend beyond thelateral sides of the deck to allow the mower to cut close to the sidesof various structures, e.g. to cut all the way up to a flower bed,retaining wall or the like.

Mowers of the type noted above have conventionally been restricted tosingle bladed mowers having the aforementioned small cutting width. Ifthe cutting width could be dramatically increased from say 21″ to 30″ orso, the user could cut 50% more grass on each cutting swath of themower. This would greatly increase productivity by decreasing the amountof time needed to mow a particular area of grass. However, such a largerwalk power mower could be stored in one's garage in much less space thanthat required for storing a riding mower. Thus, the ease of storage andgreater productivity offered by a wide swath, walk power mower would bean attractive and less expensive alternative to a riding mower.

Attempts have been made to provide larger walk power mowers having apair of side-by-side cutting blades that offer a wider cutting swaththan a single bladed mower. However, such mowers have not provided atrue rear bagging capability in the same manner as that provided by asingle bladed mower with a rearwardly extending discharge tunnel. Suchdual bladed mowers typically have discharged the grass clippings to thesides of the mower deck. The Applicants believe this to be the result ofa belief in the art that the increased volume of grass clippingsresulting from the operation of two blades could not be accommodated ina single rearwardly extending tunnel given the need to position theengine over the center of the deck in front of the bag.

Another difficulty posed by dual bladed mowers is the orientation of thecutting blades relative to one another. The two cutting blades arenormally positioned in one of two different ways: 1.) the blades can beset generally side-by-side relative to one another but staggered foreand aft relative to one another so that their cutting orbits overlap oneanother in the middle of the deck but do not intersect with one another,or 2.) the blades can be set entirely or directly side-by-side relativeto one another with no longitudinal staggering and with their cuttingorbits intersecting with one another. With the latter approach, it isnecessary to time the rotation of the dual blades relative to oneanother using a timing belt so that the dual blades do not hit oneanother as they rotate. A timing belt system requires fairly high belttension to avoid the belt from coming off the cogged timing pulleys.Such high belt tension can warp or deform the fairly light mower deckstypically used in these types of mowers.

Accordingly, it would be an advance in the art to provide a dual bladedwalk power mower that would offer a true rear bagging mode and yet bedurable and affordable.

SUMMARY OF THE INVENTION

One aspect of this invention relates to a mower which comprises a mowerdeck having at least one rotary cutting blade. A plurality of groundengaging wheels is carried on the mower deck for supporting the mowerdeck for rolling over the ground. An upwardly and rearwardly extendinghandle assembly is carried on the mower deck to permit an operator whois walking on the ground behind the mower deck to grip the handleassembly to guide and manipulate the mower deck during movement of themower deck. A power source is carried atop the mower deck for rotatingthe cutting blades. A height of cut adjustment system is provided forraising and lowering the wheels on the mower deck to adjust how far theat least one rotary cutting blade is positioned above the ground. Theheight of cut adjustment system comprises a plurality of notches,detents or openings provided in the mower deck. The height of cutadjustment system further comprises at least one spring arm that isresiliently biased towards the mower deck to move a locking pin or tabon the spring arm into engagement with a selected one of the notches,detents or openings with the height of cut being determined by whichnotch, detent or opening has been engaged by the locking pin or tab. Thelocking pin or tab is releasably coupled by a fastener to the spring armsuch that the locking pin or tab can be replaced on the spring arm ifthe locking pin or tab is damaged without having to replace the springarm.

BRIEF DESCRIPTION OF THE DRAWINGS

This invention will be described more completely in the followingDetailed Description, when taken in conjunction with the followingdrawings, in which like reference numerals refer to like elementsthroughout.

FIG. 1 is a front perspective view of one embodiment of a moweraccording to this invention, particularly illustrating the mower in amulching mode;

FIG. 2 is a top plan view of the mower of FIG. 1;

FIG. 3 is a side elevational view of the mower of FIG. 1;

FIG. 4 is a rear perspective view of the mower of FIG. 1;

FIG. 5 is a perspective view of a portion of the underside of the mowerof FIG. 1,

FIG. 6 is a perspective view of the mower of FIG. 1, but showing themower with the side discharge opening having been opened with the sidedischarge chute in place, and also showing the rear bag having beeninstalled at the rear of the mower in mating engagement with therearwardly extending grass discharge tunnel, thereby illustrating boththe side discharge and rear bagging modes of the mower;

FIG. 7 is a front perspective view of the components of the mower deck,namely of the engine mount, the deck shell and the deck shroud, thatform the mower deck of the mower of FIG. 1, particularly illustratingthe components in an exploded form;

FIG. 8 is a rear perspective view showing the deck of FIG. 7 with thedeck shroud having been exploded away from the assembled engine mountand deck shell;

FIG. 9 is a top plan view of the mower deck of FIG. 7;

FIG. 10 is a top plan view of a portion of the mower of FIG. 1,particularly illustrating the blade drive system comprising the dualcogged drive pulleys and the timing belt entrained around such drivepulleys;

FIG. 11 is a perspective view of the blade drive system of FIG. 10, butshowing one of the cogged drive pulleys in exploded form with the timingbelt having been removed;

FIGS. 12 and 13 are top plan views illustrating the operation of a belttensioning mechanism that is part of the blade drive system of FIG. 10;

FIG. 14 is an exploded perspective view of a portion of a height of cutadjustment device for the mower of FIG. 1, particularly illustrating aremovable insert forming a locking pin used on a locking spring arm inthe height of cut adjustment device;

FIG. 15 is a front perspective view of the deck shell of the mower deckof the mower of FIG. 1, particularly illustrating a side discharge chutehaving been installed on a side discharge opening on the deck shell;

FIG. 16 is an enlarged perspective view of the side discharge chute ofFIG. 15, particularly illustrating the chute in an exploded orientationrelative to the side discharge opening with a flow cutoff baffle beingcarried on the chute adjacent a rear wall of the chute;

FIG. 17 is a bottom plan view of the deck shell of FIG. 15, particularlyillustrating the side discharge chute in place on the deck shell withthe flow cutoff baffle extending inwardly through the side dischargeopening into a portion of the cutting chamber;

FIG. 18 is a perspective view of the side discharge chute of FIG. 15looking inwardly from an outboard side to an inboard side of the chute;and

FIG. 19 is a perspective view of the side discharge chute of FIG. 15looking outwardly from an inboard side to an outboard side of the chute.

DETAILED DESCRIPTION

A first embodiment according to this invention of a mower for cuttinggrass is generally illustrated as 2 herein. Mower 2 comprises a mowerdeck 4 supported for rolling over the ground by four rotatable, groundengaging wheels 6 carried at the four corners of deck 4. A U-shapedhandle assembly 8 is attached to mower deck 4 comprising a pair ofupwardly and rearwardly extending handle tubes 10 which are connectedtogether at their upper ends by a substantially horizontal cross bar 12.Cross bar 12 is wide enough to allow a user who stands on the groundbehind mower 2 to grip and hold cross bar 12 with both hands. Cross bar12 can optionally slide up and down on handle tubes 10 to vary theground speed of mower 2 as disclosed in the assignee's U.S. Pat. No.6,082,083, which is hereby incorporated by reference.

A power source comprising an internal combustion engine 14 is mountedatop deck 4. Engine 14 powers a transmission (not shown) for propellingthe rear wheels 6 of mower 2 to cause mower 2 to be self-propelled.Engine 14 also powers a pair of grass cutting blades 16 through a bladedrive system 18. Any suitable transmission or wheel drive system couldbe used on mower 2 and need not be further discussed herein. However,blade drive system 18 comprises one aspect of this invention and willthus be described in more detail hereafter.

Mower 2 operates either in a mulching mode, a side discharge mode, or arear bagging mode. In the mulching mode, the grass clippings areconfined within deck 4 until the clippings are forced or fall downwardlythrough an open bottom 66 of deck 4. In the side discharge mode, a sidedischarge opening 20 is open to allow the clippings to be thrown frommower 2 to one side of deck 4. Finally, in the rear bagging mode, a reardischarge opening 22 formed by the rear end of a rearwardly extendinggrass discharge tunnel 24 is open. This allows the clippings to bethrown through tunnel 24 and out through discharge opening 22 into aspace that is laterally positioned between lower portions of handletubes 10 when viewed from above as indicated by the tunnel dischargearrow S in FIG. 2. The clippings discharged from tunnel 24 are receivedin a grass collection bag 26 that has a mouth mated with rear dischargeopening 22. As shown in FIG. 6, bag 26 extends substantially straightback in a rearward direction from mower deck 4 to terminate in a rearend 27 that lies beneath upper portions of handle tubes 10.

The user configures mower 2 for operation at any given time in only oneof the three possible modes of operation. FIGS. 1-5 depict mower 2configured for operation in the mulching mode. In the mulching mode,side discharge opening 20 is blocked by a pivotal side door 28 andtunnel 24 is blocked or closed by a pivotal rear door 30. Tunnel 24 canbe additionally blocked by a removable mulch plug (not shown) that isinserted into tunnel 24 in the mulching mode. FIG. 6 shows side door 28having been pivoted upwardly to open side discharge opening 20 with aside discharge chute 160 having been installed on side discharge opening20. For convenience, FIG. 6 also shows rear door 30 having been pivotedupwardly to open tunnel 24 with bag 26 being mated to tunnel 24. WhileFIG. 6 has been used to show mower 2 as it would appear in both the sidedischarge and the rear bagging modes, it should be understood that bothof these modes would not be used simultaneously, i.e. the user wouldpick either the side discharge mode or the rear bagging mode.

Referring now to FIGS. 7-10, three primary components comprise deck 4,i.e. an engine mount 32, a deck shell 34, and a rear deck shroud 36.These components are screwed or bolted together to form deck 4. As shownin FIGS. 1-5, deck 4 also includes a front bracket 38 that is secured orattached, e.g. bolted, to the front of deck shell 34. Front bracket 38is used for mounting the front wheels 6 of mower 2 to deck 4. Whilefront bracket 38 also is part of deck 4, it need not be described in asmuch detail as engine mount 32, deck shell 34 and rear shroud 36.

Turning first to FIG. 7, engine mount 32 is formed with a downwardlyfacing, U-shaped engine deck 40 having a top wall 42 that is providedwith a large circular opening 44 for receiving the drive shaft (notshown) of engine 14. Engine 14 is mounted atop the top wall 42 of enginedeck 40 over the drive shaft receiving opening 44 by being bolted to topwall 42 at various locations. In addition, engine mount 32 is formedwith an upwardly facing U-shaped trough 46 immediately contiguous to aninnermost sidewall 48 of engine deck 40. Innermost sidewall 48 of enginedeck 40 also does double duty by serving as the innermost sidewall oftrough 46. A substantially horizontal front apron 50 extends forwardlyfrom the front of engine deck 40 and trough 46. Preferably, engine deck40, trough 46 and apron 50 of engine mount 32 are collectively formed asa single, one-piece cast aluminum part having a wall thickness ofapproximately 140 thousandths of an inch (0.140″) to provide greatstrength.

As shown in FIG. 7, apron 50 of engine mount 32 includes two relativelysmall circular openings 52 for receiving the upper ends of a pair ofspindles 80 that mount cutting blades 16. Each opening 52 is surroundedby four threaded apertures 56. As will be explained in more detailhereafter, fasteners 86 will be tightened into apertures 56 to attachengine mount 32 to deck shell 34 and to a pair of bearing housings 82which carry spindles 80.

Deck shell 34 is the part of deck 4 that forms a cutting chamber 60which encloses blades 16. Shell 34 comprises an integral, one-piecestamped steel part having a wall thickness that is approximately onethird thinner than the wall thickness of the cast aluminum engine mount32, i.e. a wall thickness of approximately 90 thousandths of an inch(0.090″) for shell 34. Shell 34 has a top wall 62 that is bounded by aperipheral, downwardly extending sidewall 64 to form cutting chamber 60.Cutting chamber 60 has an open bottom 66 that faces downwardly towardsthe ground. See FIG. 8. A circumferential lip 67 extends a shortdistance outwardly from a lower edge of sidewall 64.

Sidewall 64 of shell 34 is interrupted in two places to form sidedischarge opening 20 as well as a rear outlet 68. See FIGS. 15 and 16. Aportion of outlet 68 is formed in sidewall 64 of shell 34 and a portionof outlet 68 is formed in top wall 62 of shell 34. Outlet 68 is mated tothe inlet or entrance to tunnel 24 so that clippings generated withincutting chamber 60 pass upwardly from cutting chamber 60 of shell 34through outlet 68 into the front end of tunnel 24. In addition, shell 34includes a shallow recessed central portion 70 having a depthapproximately equal to the wall thickness of apron 50. Central portion70 includes two circular openings 72 that correspond in size, shape andrelative location to circular openings 52 in apron 50 of engine mount32. Circular openings 72 are each surrounded by four smooth apertures76.

Apron 50 of engine mount 32 can be nested down within recessed centralportion 70 when engine mount 32 and shell 34 are assembled together withcircular openings 52, 72 in both parts and surrounding apertures 56, 76being superimposed on top of one another. In addition, engine mount 32wraps closely around the rear face of peripheral sidewall 64 with thefront ends of lower edges 73 of the sidewalls 74 of engine mount 32engaging at two spaced locations atop the rear side of lip 67 of shell34. See FIGS. 7 and 8. Apertures are provided in lip 67 at theselocations that are aligned with threaded bosses 77 on sidewalls 74 toprovide a pair of attachment points between engine mount 32 and shell 34that are in addition to the eight other attachment points providedcollectively by the superimposed apertures 56, 76.

As best shown in FIGS. 7 and 8, deck shroud 36 is L-shaped having aU-shaped, downwardly facing channel 78 along one side of shroud 36.Channel 78 in shroud 36 is substantially the same size and shape astrough 46 in engine mount 32. When shroud 36 is screwed or bolted toengine mount 32, trough 46 in engine mount 32 and channel 78 in shroud36 together form tunnel 24. Trough 46 forms the lower portion of tunnel24 and channel 78 forms the upper portion of tunnel 24. Shroud 36preferably comprises an integral, one-piece molded plastic part.

Referring now to FIGS. 5 and 10, two spindles 80 extend into cuttingchamber 60 with blades 16 being bolted to bottom ends of spindles 80.Spindles 80 are rotatably supported by bearings (not shown) containedwithin bearing housings 82. Each bearing housing 82 is cast from metalas a single piece. In addition, each bearing housing 82 has fouroutwardly extending mounting arms 84 containing apertures at the ends ofarms 84. The apertures at the end of arms 84 have the same spacing andorientation as apertures 56, 76 in top wall 62 of shell 34 and in apron50 of engine mount 32.

In assembling deck 4 from its primary components, bearing housings 82are installed in cutting chamber 60 of shell 34 with arms 84 abuttingthe underside of top wall 62 of shell 34. Engine mount 32 is laid on topwall 62 of shell 34 with apron 50 being received in recessed portion 70.Threaded fasteners 86, such as machine bolts, are then passed up throughthe apertures at the ends of arms 84 on each bearing housing 82 andthrough the aligned apertures 76, 56 to be screwed upwardly into thefour threaded apertures 56 on engine mount 32. When fasteners 86 aretightened into apertures 56, spindles 80 carried in bearing housings 82are each securely bolted to the relatively thick, cast aluminum apron 50of engine mount 32 with the stamped steel top wall 62 of shell 34 beingtightly sandwiched between apron 50 and bearing housings 82. Thisprovides a very strong and durable structure for deck 4 that issufficient for withstanding relatively high tension in the drive beltused to power spindles 80 without warping deck 4. This strength anddurability is further enhanced by the two additional fasteners 88 thatbolt lower edges 73 of sidewalls 74 of engine mount 32 to lip 67 ofshell 34. See FIG. 5.

Blades 16 are arranged side-by-side relative to one another with theorbits of the tips of blades 16 intersecting one another along themiddle of shell 34. As best shown in FIG. 8, blades 16 are oriented atright angles relative to one another which orthogonal orientation ismaintained by blade drive system 18 so that blades 16 do not hit oneanother as they rotate. Referring to FIG. 5, blade drive system 18rotates each blade 16 in the same rotational direction indicated by thearrow A. Thus, the clippings cut by blades 16 circulate in acircumferential path inside cutting chamber 60 defined by a shallowdownwardly facing channel 63 in top wall 62 formed between sidewall 64and recessed central portion 70. The circumferential path of thecirculating clippings is indicated by the arrows B in FIG. 5 which showthat such path is directed first towards side discharge opening 20 andthen to tunnel 24 should side discharge opening 20 be closed.

There are no interior flow control baffles used in the circumferentialpath B that serve to separate one blade 16 from the other. This permitsthe clippings generated by the action of both blades 16 to smoothlymerge into one common stream. The only baffle of any type used incutting chamber 60 is a rear generally V-shaped baffle 90 at the back ofcutting chamber 60 having an apex 92 that faces towards the front ofcutting chamber 60.

FIGS. 10 and 11 depict blade drive system 18 that powers the dualcutting blades 16 of mower 2 of this invention. Engine 14 has beenremoved from FIGS. 10 and 11 for the sake of clarity. However, two drivebelts 94 and 96 that would be powered by the drive shaft of engine 14are still shown in FIGS. 10 and 11. As shown in FIG. 10, drive belt 94extends to the rear of engine deck 40 for powering the transmission (notshown) that drives rear wheels 6. As shown in FIG. 11, drive belt 96extends to the front of engine deck 40 outwardly through an accessopening 98 in the front wall of engine deck 40. As further shown in FIG.11, drive belt 96 is entrained around a driven pulley 100 on the top ofleft spindle 80 to rotate the left spindle and thereby rotate leftcutting blade 16. When referring to the left or right spindles orcutting blades, the adjectives left and right are used with reference toa user who is standing behind mower 2 looking forwardly.

A cogged timing pulley 102 is located on the right spindle 80 that isbolted to the right cutting blade 16. An identical cogged pulley 104 islocated beneath the driven pulley 100 on the left spindle 80 for theleft cutting blade 16. Both cogged pulleys 102 and 104 are located onthe upper ends of spindles 80 and lie substantially immediately aboveapron 50 of engine mount 32. A cogged timing belt 106 passes aroundpulleys 102 and 104 to maintain the necessary rotational timing betweenspindles 80. Remember that blades 16 are to be disposed offset relativeto one another by 90°. It is cogged timing belt 106 in engagement withcogged pulleys 102 and 104 that maintains this offset to ensure thatblades 16 do not strike one another even though their orbits intersect.

A belt cover 108 normally covers blade drive system 18 including bothtiming pulleys 102 and 104 and timing belt 106. Belt cover 108 is shownin place FIGS. 1-4 and 6 but has been removed from FIGS. 10 and 11 forthe sake of clarity. Belt cover 108 is usually held in place byreleasable fasteners 110 as shown in FIG. 2 that can be screwed intoupwardly extending threaded bosses 112 as shown in FIG. 7 that areprovided on engine mount 32.

In initially assembling mower 2 or whenever timing belt 106 needs to bereplaced, a unique and easy to use locator system 114 is provided forlocating timing pulleys 102 and 104 in their correct positions. As bestshown in FIG. 11, locator system 114 comprises a guide hole 116 locatedin apron 50 of engine mount 32 adjacent each of the circular openings 42in apron 50 through which spindles 80 extend. Guide hole 116 for opening52 that receives the left spindle 80 is located at a 6 o'clock positionwhile guide hole 116 for opening 52 that receives the right spindle 80is located at a 9 o'clock position. Thus, the two guide holes 116 areoffset from one another by 90°. Guide holes 116 do not extend throughinto cutting chamber 60 as they are blocked by an underlying portion ofdeck shell 34 or alternatively because they are formed only partiallythrough the thickness of apron 50.

Each timing pulley 102 and 104 has a through hole 118 located on aradius that overlies guide holes 116. In addition, timing pulleys 102and 104 and spindles 80 are configured so that they pulleys 102 and 104can be installed on spindles 80 in only one orientation. Thus, the usercan align through hole 118 in timing pulley 102 with guide hole 116adjacent the opening for the right spindle 80 and then drop a pin or rod(not shown) through the aligned holes 118 and 116 to locate timingpulley 102 in exactly the correct position to hold the right cuttingblade 16 at the correct orientation within cutting chamber 60. The samething can be done with through hole 118 for timing pulley 104 for theleft spindle 80 and its corresponding guide hole 116.

When this procedure is followed, both timing pulleys 102 and 104 havebeen simply and easily located in the correct positions so that cuttingblades 16 are correctly offset 90° from one another. This avoids theuser having to continually look beneath top 62 wall of shell 34 tomanually and visually observe the two blades 16 and attempt to positionthem by hand at the required offset. The alignment of through holes 118in timing pulleys 102 and 104 with the offset guide holes 116 providedin deck 4 and the use of a temporarily inserted bolt though the alignedsets of holes automatically does the same thing. The user can theninstall timing belt 106 around the timing pulleys 102 and 104 withcertainty that blades 16 are in their correct offset positions. Aftertiming belt 106 has been so installed, the bolts used to temporarilyhold timing pulleys 102 and 104 in place can be pulled upwardly out ofthrough holes 118 in timing pulleys 102 and 104.

Timing belt 106 is appropriately tensioned by passing around two idlerpulleys 120 and 122 that engage the smooth backside of timing belt 106.Idler pulley 120 rotates around a fixed vertical pivot axis 121 on deck4. However, the other idler pulley 122 rotates around a vertical pivotaxis 123 that is carried on an adjustable slide 124. Slide 124 isL-shaped having a vertical front wall 126 and a rearwardly extendingbottom wall 128. As best shown in FIG. 10, bottom wall 128 has a pair ofslots 130 for receiving the shanks of a pair of shoulder bolts 132 thatcan be tightened into a pair of upwardly facing threaded apertures inapron 50 of engine mount 32 of deck 4. However, when shoulder bolts 132are fully tightened, such bolts 132 do not clamp or lock slide 124 inplace, but in conjunction with slots 130 serve as guides for the backand forth sliding motion of slide 124.

Slide 124 is contained within a U-shaped channel 134 that is a fixedpart of apron 50 of engine mount 32. The front wall 136 of channel 134is spaced away by a relatively short distance from front wall 126 ofslide 124 with both front walls 126 and 136 being parallel to oneanother. A threaded adjustment bolt 138 has its head 140 in engagementwith front wall 136 of channel 134 with the shank of bolt 138 passingthrough aligned openings in front walls 126 and 136 of slide 124 andchannel 134, respectively. The rear end of the shank of bolt 138 isthreaded to receive a threaded nut 142 located behind front wall 126 ofslide 124.

The required tension in timing belt 106 can be easily set by rotatingnut 142 and bolt 138 relative to one another to cause slide 124 to beslid on apron 50 in one direction or the other. If bolt 138 is rotatedin one direction relative to nut 142, the rotation of bolt 138 will pullslide 124 forwardly towards front wall 126 of channel 134, therebymoving the adjustable idler pulley 122 forwardly to increase the tensionin timing belt 106. Once slide 124 has been moved far enough forwardlyto put enough tension on timing belt 106, the user can stop the relativerotation of bolt 138 and nut 142 to hold idler pulley 122 in itsadjusted position. All of this can be done from above and from the frontof deck 4 once belt cover 108 is temporarily removed since head 140 ofbolt 138 and nut 142 are exposed to and easily reached by the user fromabove and from the front of deck 4. This makes setting the tension intiming belt 106 extremely easy.

Referring now to FIGS. 12 and 13, a simple leaf spring 144 is interposedbetween head 140 of bolt 138 and the front side of front wall 126 ofchannel 134. When the tension in timing belt 106 is too loose with slide124 being disposed too far to the rear in channel 134, leaf spring 144will be bowed out as indicated in FIG. 12. However, as the user turnsbolt 138 to draw slide 124 towards the front to increase the tension intiming belt 106, leaf spring 144 will eventually substantially flattenout to become more tightly sandwiched between head 140 of bolt 138 andfront wall 126 in channel 134 as shown in FIG. 13. The force requiredfor leaf spring 144 to substantially flatten out (i.e. being within arange of from 0.010″ to 0.030″ of wall 126) is chosen to correspond tothe moment in time when the tension on timing belt 106 reaches thedesired level. Thus, once the user sees leaf spring 144 substantiallyflatten out, the user knows that the tension in timing belt 106 has beenadjusted to the correct level and can stop turning bolt 138. Thesubstantial flattening out of leaf spring 144 thus forms an inexpensive,durable and easily read indicator that informs the user when timing belttension has been correctly set.

Referring now to FIGS. 2 and 6, tunnel 24 is located on the right sideof mower deck 4 and extends rearwardly to discharge the clippings intorear collection bag 26. The Applicants have found a way to providetunnel 24 with sufficient volumetric capacity to handle the volume ofgrass clippings being generated by the operation of the dualside-by-side cutting blades 16. Each cutting blade 16 is slightly longerthan 15″ in length so that the combined swath cut by both blades is 30″.Yet, tunnel 24 still fits atop deck 4 without protruding beyond thesides of shell 34 of deck 4. Thus, the sides of deck 4 can still closelyabut up to obstacles, such as the edges of a flower bed, since thewheels of mower 2 are also inset from the extreme outermost edges of thesides of deck 4. Thus, mower 2 of this invention handles like aconventional smaller sized consumer mower having a rear bagging mode,yet cuts 50% more grass on each swath of mower 2. This is a significantadvance in the art.

A number of factors help provide mower 2 of this invention with theability to use a single tunnel 24 to collect the clippings from twocutting blades 16 that provide a significant increase in the width ofcut with such single tunnel lying on or inboard of the side edges of themower deck and with such single tunnel discharging the clippings to therear of the mower deck. First, as best shown in FIG. 9, engine 14 hasbeen shifted off center to the left of the longitudinal centerline c₁ ofdeck 4 by a distance of 1.7 inches. This offset is indicated in FIG. 9by the gap g between centerline c₁ and the axis of the drive shaft ofengine 14 which drive shaft axis will be aligned with the center c ofopening 44 in the top wall 42 of engine deck 40. This shift of engine 14to the left of more deck provides more space for a wider tunnel 24 onthe right of mower deck 4.

Second, as also shown in FIG. 9 as well as FIGS. 10 and 11, blade drivesystem 18 has been configured so that most of the components thereof arealso located on the left side of mower deck 4 to the left of centerlinec₁. For example, drive belt 96 that extends to driven pulley 100,spindle 80 for the left cutting blade 16 and timing pulley 104 for suchspindle 80, the adjustable idler pulley 122 and the adjustable slide 124that mounts pulley 122 are all on the side of mower deck 4 that is awaytunnel 24. Only, the fixed idler pulley 120 and the spindle 80 for theright cutting blade along with timing pulley 102 are located on theright of mower deck 4 to the right of centerline c₁. This minimizes thespace taken up on the right or tunnel side of mower deck 4 by bladedrive system 18. Thus, as shown in FIG. 2, belt cover 108 is muchsmaller in a fore and aft direction on the tunnel side of mower deck 4than on the non-tunnel side of mower deck 4, thereby allowing tunnel 24to extend further forwardly on mower deck 4 than would have been thecase if drive belt 96 or the idler pulley 122 and slide 124 had beenreversed in their positions.

Thirdly, as best shown in FIG. 3, tunnel 24 progressively increases inheight as it extends rearwardly. Moreover, tunnel 24 increases in widthas it extends rearwardly as indicated by the inclined innermost sidewall48 of engine deck 40. This gets as much volume as possible into tunnel24. All of these factors contribute to the use of a single tunnel 24 fordischarging grass clippings to the rear in the manner of a typical walkpower mower having rear bagging capability, though one or more of thefactors could potentially be dropped. The most important of the factorsis offsetting the engine somewhat to the non-tunnel side of mower deck 4to provide more absolute space of tunnel 24.

While use of a single tunnel 24 has been described above in anembodiment in which two side-by-side cutting blades are positioned tohave intersecting orbits, blades 16 could alternatively be positioned ina side-by-side arrangement in which blades 16 are longitudinallystaggered to have non-intersecting orbits that still overlap one anotherin the middle. In this alternative arrangement, the right side of theorbit of one blade will lie behind or in front of the left side of theorbit of the other blade to ensure that no uncut grass is left in themiddle of the swath even though the orbits never cross one another. Thefactors noted above contributing to the use of a single, rearwardlyextending grass discharge tunnel 24 on a mower could still be employedon a mower having this alternative arrangement of side-by-side cuttingblades 16. However, the alternative arrangement is slightly lesspreferred than the embodiment specifically described herein as itincreases the front to back length of mower deck 4.

Referring now to FIG. 14, mower 2 of this invention employs a generallyconventional height of cut adjustment system that adjusts the height ofwheels 6 up and down relative to mower deck 4 to change the height ofblades 16 above the ground. The height of cut adjustment system that isemployed is one that uses at least one pivotal spring arm 146 thatpivots about a horizontal pivot axis x relative to a series of notches,detents or openings 148 that are provided on mower deck 4. Spring arm146 is linked to at least one and possibly more than one of the wheels 6so that pivotal motion of spring arm 146 about pivot axis x lifts orlowers the axle of the wheel(s) 6 relative to mower deck 4 to move mowerdeck 4, and thus cutting blades 16, upwardly or downwardly relative toground. In prior art systems of this kind, the spring arm carries anintegrally formed locking pin or tab that engages with one of the seriesof notches, detents or openings to hold the wheel or wheels 6 in anadjusted position.

As shown in FIG. 14, spring arm 146 according to this invention employsa channel 150 on the back thereof, i.e. on that part of spring arm 146that faces notches, detents or openings 148. A removable insert 151 isprovided comprising a locking pin or tab 152 that is formed with andprojects from one side of a base 154. Base 154 is shaped to be receivedclosely within the confines of channel 150 on a flat portion 156 ofchannel 150. An attachment screw 158 is used to releasably attach base154 of insert 151 to channel 150 of spring arm 146 with locking pin ortab 152 suited to be received in any one of the notches, detents oropenings 148. Thus, if mower 2 hits an obstacle and a shear load isimposed on locking pin or tab 152 that would tend to break off pin ortab 152, the user need only replace insert 151 rather than replacing theentire spring arm 146. This is advantageous as it will be significantlyless costly and easier to replace insert 151 instead of having toreplace the complete spring arm 146.

Finally, turning to FIGS. 15-19, an improved side discharge chute 160 isshown for use with side discharge opening 20. Chute 160 is releasablymounted to mower deck 4 to extend away from side discharge opening 20and to cause the clippings exiting from side discharge opening 20 to bethrown safely to the side of mower deck 4. Chute 160 is mounted to mowerdeck 4 after side door 28 is first pivoted upwardly as shown in FIG. 15.Various ways of attaching chute 160 to deck 4 can be used, such as holesor apertures 162 that can be dropped over pins or tabs (not shown) onmower deck 4. See FIG. 16 in which chute 160 has been pulled away fromdeck 4 and side door 28 has been removed.

As is typical of side discharge chutes, chute 160 of this invention isU-shaped with a front wall 164, a top wall 166, and a rear wall 168 thattogether form the U-shape. It is obvious that the U-shape provided bychute 160 faces downwardly towards the ground. The front wall 164 andthe rear wall 168 have been so named because front wall 164 is the firstto see clippings that are passing through side discharge opening 20 andrear wall 168 is the last to see such clippings. Put another way, frontwall 164 is upstream from rear wall 168 taken with respect to thedirection B in which the clippings are circulating within cuttingchamber 60 past side discharge opening 20.

Referring more particularly to FIGS. 15-19, chute 160 of this inventionincludes a flow cutoff baffle 170 that is located substantially alongrear wall 168 of chute 160. Baffle 170 has an inner end 172 thatprotrudes inwardly from an inboard side of chute 160 to stick inwardlythrough side discharge opening 20 when chute 160 is attached to deck 4.Baffle 170 has an outer end 174 that is releasably attached by a pair ofscrews 177 to chute 160. See FIG. 18.

As best shown in FIG. 17, when chute 160 is in place, inner end 172 ofbaffle 170 protrudes into the path B of the clippings circulating withinchannel 63 of cutting chamber 60. Inner end 172 of baffle 170 is alsoobviously above the plane of rotation of blades 16 to avoid being struckby the blade 16 that is nearest to baffle 170 as inner end 172 of baffle170 partially overlies the orbit of that nearest blade. The inner end172 of baffle 170 has a substantially front face 176 that serves tointercept the clippings and assist the clippings into passing throughside discharge opening 20 into chute 160. This helps improve sidedischarge efficiency by greatly decreasing the amount of clippings thatmight miss side discharge opening 20 to keep circulating within cuttingchamber 60. This increase in efficiency helps improve how far theclippings are thrown to the side from deck 4.

Baffle 170 is formed as an integral one-piece plastic part. Baffle 172has a three dimensional shape with inner end 172 having a rear face 178behind front face 176 with a number of bracing ribs 180 extendingbetween the two faces 176 and 180. See FIG. 16. In addition, outer end174 of baffle 170 has a pair of ribs 182 arranged in a V-shape thatfurther brace baffle 170 against the top and rear walls 166 and 168 ofchute 160. This structure helps baffle 170 resist impacts from anyforeign objects, such as rocks or other debris, which might be picked upand carried with the clippings to resist being damaged or bent from suchimpact. However, should baffle 170 be damaged, it is easily replaceableas it is releasably attached to chute 160.

Chute 160 of this invention incorporates flow cutoff baffle 170 thereonso that it is in place only when chute 160 is in place after the userhas selected the side discharge mode of operation. If chute 160 is takenoff and side door 28 is closed to block side discharge opening 20,baffle 170 is gone as it is not a permanent part of mower deck 4. Thus,baffle 170 does not hinder or prevent operation of mower 2 it themulching or rear bagging modes of operation, as it would had baffle 170been made part of mower deck 4 instead of being carried on chute 160.

Various modifications of this invention will be apparent to thoseskilled in the art. While an internal combustion engine 14 has beenshown as the power source herein, other power sources, e.g. an electricmotor powered by some source of electrical energy, could be used.Similarly, the pivotal side door 28 used to open and close sidedischarge opening 20 could be replaced by an installable and removableblocking plate. Rather than using cogged pulleys engaged by a coggedbelt, one could use cogged sprockets engaged by a cogged chain in whichthe cogs are formed by the links in the chain. Thus, the scope of thisinvention will be limited only by the appended claims.

The invention claimed is:
 1. A walk power mower, which comprises: (a) amower deck having at least one rotary cutting blade; (b) a plurality ofground engaging wheels carried on the mower deck for supporting themower deck for rolling over the ground; (c) an upwardly and rearwardlyextending handle assembly carried on the mower deck to permit anoperator who is walking on the ground behind the mower deck to grip thehandle assembly to guide and manipulate the mower deck during movementof the mower deck; (d) a power source carried atop the mower deck forrotating the cutting blades; and (e) a height of cut adjustment systemfor raising and lowering the wheels on the mower deck to adjust how farthe at least one rotary cutting blade is positioned above the ground,the height of cut adjustment system comprising: (i) a plurality ofnotches, detents or openings provided on the mower deck; (ii) at leastone spring arm that is resiliently biased towards the mower deck to movea locking pin or tab on the spring arm into engagement with a selectedone of the notches, detents or openings with the height of cut beingdetermined by which notch, detent or opening has been engaged by thelocking pin or tab, wherein the spring arm has an inner side that facesthe detents, notches or openings with the inner side of the spring armhaving a substantially flat portion, wherein the locking pin or tab isformed with and projects from one side of a substantially flat base thatis mounted against the substantially flat portion of the inner side ofthe spring arm, wherein the substantially flat portion of the inner sideof the spring arm comprises a substantially flat vertical wall havinginturned side edges to form a shallow channel that faces inwardlytowards the notches, detents or openings, and wherein the base thatcarries the locking pin or tab is shaped to be received closely withinthe channel with the base having a lateral width between opposite sidesthereof which is approximately equal to but slightly less than a lateraldistance between the side edges of the channel such that the oppositesides of the base are substantially directly contiguous to the sideedges of the channel when the base is received within the channel; and(iii) wherein the locking pin or tab is releasably coupled by anelongated, substantially horizontal, threaded fastener to the spring armsuch that the locking pin or tab can be replaced on the spring arm ifthe locking pin or tab is damaged without having to replace the springarm, the substantially directly contiguous side edges of the channel andthe opposite sides of the base being straight and in a substantiallyabutting engagement with one another when the base is received in thechannel to non-rotatably hold the base within the channel when the baseis received in the channel such that rotation of the threaded fastenerin opposite directions is effective to clamp and unclamp, respectively,the base within the channel instead of rotating the base relative to thechannel.
 2. The mower of claim 1, wherein the lateral width of the basethat carries the locking pin or tab substantially exceeds a lateralwidth of the locking pin or tab.
 3. The mower of claim 1, wherein thespring arm has a substantially horizontal hole that passes through athickness of the spring arm between an outer side of the spring arm andthe inner side of the spring arm with the hole being located on thesubstantially flat portion on the inner side of the spring arm, andwherein the threaded fastener passes inwardly from the exterior side ofthe spring arm, through the hole in the spring arm and into the basethat carries the locking pin or tab to releasably couple the locking pinor tab to the spring arm.